Rolling skates are widely popular, and are frequently found in the form of roller skates and in-line skates. When using existing skates, a user is propelled forward by the user applying a lateral, forward-facing force against the wheels of alternating ones of the skates. This lateral force moves the user forward.
In order to apply this lateral force, the user must twist his or her leg outward and push outward and backward. This pushing creates strain on the user's knees which can cause injury or pain.